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Energy & Power

The Museum's collections on energy and power illuminate the role of fire, steam, wind, water, electricity, and the atom in the nation's history. The artifacts include wood-burning stoves, water turbines, and windmills, as well as steam, gas, and diesel engines. Oil-exploration and coal-mining equipment form part of these collections, along with a computer that controlled a power plant and even bubble chambers—a tool of physicists to study protons, electrons, and other charged particles.

A special strength of the collections lies in objects related to the history of electrical power, including generators, batteries, cables, transformers, and early photovoltaic cells. A group of Thomas Edison's earliest light bulbs are a precious treasure. Hundreds of other objects represent the innumerable uses of electricity, from streetlights and railway signals to microwave ovens and satellite equipment.

Irving Langmuir received a Ph.D. in physical chemistry in 1906 from the University of Göttingen. He studied under Walther Nernst, who had invented a new type of incandescent lamp only a few years before. In 1909 Langmuir accepted a position at the General Electric Research Laboratory in Schenectady, New York. Ironically, he soon invented a lamp that made Nernst's lamp (and others) obsolete.

Langmuir experimented with the bendable tungsten wire developed by his colleague William Coolidge. He wanted to find a way to keep tungsten lamps from "blackening" or growing dim as the inside of the bulb became coated with tungsten evaporated from the filament. Though he did not solve this problem, he did create a coiled-tungsten filament mounted in a gas-filled lamp—a design still used today.

Up to that time all the air and other gasses were removed from lamps so the filaments could operate in a vacuum. Langmuir found that by putting nitrogen into a lamp, he could slow the evaporation of tungsten from the filament. He then found that thin filaments radiated heat faster than thick filaments, but the same thin filament–wound into a coil–radiated heat as if it were a solid rod the diameter of the coil. By 1913 Langmuir had gas–filled lamps that gave 12 to 20 lumens per watt (lpw), while Coolidge's vacuum lamps gave about 10 lpw.

During the 1910s GE began phasing-in Langmuir's third generation tungsten lamps, calling them "Mazda C" lamps. Although today's lamps are different in detail (for example, argon is used rather than nitrogen), the basic concept is still the same. The lamp seen here was sent to the National Bureau of Standards in the mid 1920s for use as a standard lamp.

Lamp characteristics: Brass medium-screw base with skirt and glass insulator. Two tungsten filaments (both are C9 configuration, mounted in parallel) with 6 support hooks and a support attaching each lead to the stem. The stem assembly includes welded connectors, angled-dumet leads, and a mica heat-shield attached to the leads above the press. The shield clips are welded to the press. Lamp is filled with nitrogen gas. Tipless, G-shaped envelope with neck.

The Halarc lamp was an attempt by General Electric to produce an energy-efficient replacement for the common, incandescent A-lamp. While other makers focused on developing reliable compact fluorescent lamps, GE decided to miniaturize its metal halide technology. Already successful for street lighting, large metal halide lamps provided good color and excellent energy efficiency. Unfortunately the miniaturized lamps had undesirable performance characteristics such as taking several minutes to come to full-power and changing color emissions. These issues combined with high cost made the lamp a commercial failure.

Ordinary lamps give good quality light and can be designed for all manner of special tasks. However, they waste a tremendous amount of energy in the form of heat. The steep rise in energy prices during the 1970s spurred a burst of invention aimed at developing lamps that gave more lumens per watt—the lighting equivalent of miles per gallon in cars.

Much of the invention took place in the laboratories of major lighting companies like General Electric and Sylvania. But inventors outside the corporate labs also offered ideas and new devices. One such inventor was Donald Hollister of California. A UCLA graduate with experience in plasma physics, Hollister patented a small fluorescent lamp called the "Litek." The lamp seen here is a hand-made prototype from 1979.

Most fluorescent lamps, large and small, operate by passing an electric current through a gas between two electrodes. The current energizes the gas that in turn radiates ultraviolet (UV) light. The UV is converted to visible light by a coating of phosphors inside the glass envelope of the lamp. Electrodes are responsible for much of the energy lost in a fluorescent lamp and are usually the part of the lamp that fails. Hollister's design was "electrodeless," and used high-frequency radio waves instead of electrodes to energize the gas.

The Litek lamp worked in the laboratory, and Hollister received funding from the U.S. Department of Energy to refine the design. That proved more difficult than expected though. The electronic components available at the time were expensive and generated too much heat. Hollister tried to compensate with the massive heat-dissipation fins set below the bulb, but this added to the cost. Also, as an independent inventor Hollister could not just focus on research. He had to perform administrative tasks that researchers in corporate labs did not, and the project lagged. In the end the Litek did not reach the market, though in the 1990s the major companies all began selling electrodeless fluorescent lamps. These built on the work of several inventors, including Hollister's.

Lamp characteristics: Nickle-plated brass medium-screw base shell with brass retainer and plastic skirt. The base insulator is part of skirt. A metal fitting attaches to the skirt to dissipate heat. Tipped, G-shaped envelope with phosphor coating on inner wall and clear tip.